Nothing new on EXOS (yet). We've just created that repo to have a place to put docs and example playbooks for using the new SLX modules that we're working on here
https://github.com/StackStorm/ansible/tree/slxos_modules
I would love to also have EXOS modules in future, but nothing committed yet.
Of course, if others want to get started with writing Ansible modules, that would be great. They are all Open Source, and it's not that hard to get started with writing your own. See
https://github.com/ansible/ansible/tree/devel/lib/ansible/modules/network for all the other examples.
Modules don't have to be written by the vendor themselves. Anyone can write them. You can see that a user has written modules for MLXe (Ironware). These are in the 2.5 release, which is in final RC stage right now, and will probably go GA next week.